Abstract: In order to compare the effects of different fixations on paraffin section H.E.staining of Mongolian horse testes before and after sexual maturity, testicular tissues of 1-year-old and 10-year-old Mongolian horses were collected and fixed in 4% paraformaldehyde（ 4% PFA）, Bouin’s fixative（ Bouin’s） and Davidson’s fixative（ Davidson’s）, respectively. Then paraffin sections were made and H.E.staining was performed. The effect of H.E.staining was observed under a microscope and scored. The results showed that the staining effect of 4% PFA was better than that of Bouin’s and Davidson’s fixatives for H.E. staining of 1-year-old Mongolian horse testis paraffin sections. Its staining effect scores were significantly higher than those of Bouin’s and Davidson’s fixatives in the clarity and integrity of cell morphology and the clarity of nuclear staining（P＜0.01）. For H.E. staining of 10-year-old Mongolian horse testis paraffin sections, 4% PFA and Bouin’s fixatives had similar effects, and the staining effect scores of both were significantly higher than those of Davidson’s fixative in terms of cell morphology clarity and integrity, nuclear-staining clarity, cytoplasmic staining clarity, and nuclear-cytoplasmic contrast（P＜0.01）. The above results indicated that 4% PFA had the best effect in the case of fewer cells in the seminiferous tubules before sexual maturity of Mongolian horses, however, in the case of more cells in the seminiferous tubules after sexual maturity of Mongolian horses, 4% PFA and Bouin’s fixatives could be selected, and the effects were better.